New-drug `Explosion` Seen For Alzheimer`s

October 09, 1988|By Jon Van, Science writer.

An ``explosion`` of new drugs intended to improve the memories and behavior problems of people with Alzheimer`s disease will be ready for human testing within a year or two, researchers in the field predict.

Indeed, so many promising new drugs are on the verge of clinical testing that scientists fear it might be very difficult to find enough suitable patients to serve as test subjects.

Several different therapies to improve cognitive function in Alzheimer`s victims have shown promise in lab and animal tests, researchers from drug companies said at a seminar sponsored by the National Pharmaceutical Council in Chicago last week.

The seminar was held in conjunction with this weekend`s annual meeting of the Alzheimer`s Disease and Related Disorders Association, which is headquartered here.

There are currently no approved therapies to treat the loss of memory and other dementia symptoms associated with the disease, although patients often receive tranquilizers, antidepressants and antianxiety drugs to treat the secondary effects of their disease, said Dr. Lissy Jarvik, a medical adviser to the Alzheimer group.

``Without these drugs, many patients now living at home would have to be institutionalized,`` Jarvik said.

Although an estimated 2.5 million Americans suffer from Alzheimer`s disease, and even though many families are eager to participate in any drug test that offers possible help to sufferers, it is difficult to locate patients ideally suited for studying new treatments.

When scientists test a new drug, they look for patients who are healthy in every aspect except the loss of mental function caused by Alzheimer`s, explained Dr. Michael Murphy, a researcher at Hoechst-Roussel Pharmaceuticals in Somerville, N.J.

Patients who participate in new drug studies must eschew tranquilizers or other drugs that can depress cognitive function, Murphy said. Also, in most studies, patients receive the drug under scrutiny, but there is an equal chance they will get a placebo.

``A big problem is that these other drugs are helping a family cope with the illness, and we are saying you have to take the patient off those drugs and take a 50-50 chance of getting a shot at a real drug being tested,``

Murphy said.

Patients whose mental functions are deteriorated badly aren`t suitable for testing, Jarvik explained, because they cannot perform cognitive tests needed to determine if the therapy is producing some benefit.

And patients in an early stage of the disease may not participate in a study because they and their families still deny they really have Alzheimer`s disease, she added.

Diagnosis is another problem in the Alzheimer`s equation because the only definitive way to prove a person had the disease is after death, when a brain biopsy will show physical damage to brain tissue that is a sure sign of the affliction.

But in living patients, especially those in the early stages of the disease, doctors cannot diagnose Alzheimer`s with absolute certainty.

New techniques seeking biological markers that can confirm Alzheimer`s disease with high confidence levels in living patients will help physicians find patients who are good candidates for early treatment or for clinical tests of new drugs, according to Dr. Robert Frederickson, a researcher for Searle Laboratories in Skokie.

Several new methods for more accurate diagnosis should be available within a few years, Frederickson said.

Only three compounds intended to improve cognitive function are now being tested in humans, Murphy said. They are being used at nearly two dozen major medical centers across the country.

Once a few more new drugs enter clinical trials, most major medical centers in the United States with the necessary research talent will be participating in a study of some kind.

It takes cooperation among several medical centers, including hundreds or thousands of patients, to provide enough information to assure that a new drug is both safe and effective, Murphy noted.